農業気象
Online ISSN : 1881-0136
Print ISSN : 0021-8588
ISSN-L : 0021-8588
46 巻, 3 号
選択された号の論文の8件中1~8を表示しています
  • 小元 敬男, 青野 靖之
    1990 年 46 巻 3 号 p. 123-129
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
    It has been known that cherry trees in the central area of a large city come into blossom earlier than those in the suburbs. One of the main causes of this advancement of blooming dates is urban warming. The purpose of this paper is to show the relationship between the amount of urban warming (ΔTu), and the amount of advancement of blooming dates (ΔBDu). Data used in this study are official records of blooming dates of Prunus yedoensis (the most popular species of cherry trees in Japan) at stations of the Japan Meteorological Agency (JMA) and daily mean temperatures at these stations.
    In oder to obtain ΔBDu which is assumed to be entirely temperature dependent, it is necessary to estimate blooming dates from temperature data. This could be made by the method reported in our previous paper (Omoto and Aono, 1989). It enables us to relate deviation of blooming dates of a particular year from mean blooming dates (ΔBD) with deviation of temperature from the normal (ΔTa). The linear relationship between ΔBD and ΔTa found at each site suggests that we can replace these parameters by ΔBDu and ΔTu respectively. The evaluation of ΔTu is made by the method proposed by Omoto and Hamotani (1979). It is pointed out that the proportional constants β at various stations differ systematically such that the earlier the mean blooming date, the smaller the value of β.
    Nevertheless there are several sources of error in the computations of ΔBDu and ΔTu, comparisons between variations of actual and estimated blooming dates in several large cities in Japan indicate that the present method gives reasonable estimation.
  • 1990 年 46 巻 3 号 p. 130
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 高谷 悟
    1990 年 46 巻 3 号 p. 131-136
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
    Rain/temperature quotient (RQ) was calculated using monthly weather data for the growing period in order to take into consideration effects of seasonal variation in air temperature and rainfall on fruit production. The RQ dependence of yields of peach and Japanese pear in major fruit producing prefectures was approximately expressed by quadratic equation. It was found that the maximum yields of peach and Japanese pear are obtained at nearly 6 and 8 of RQ values, respectively.
    A new agroclimatic index—climatic suitability index (CSI)—was introduced to evaluate agroclimatic suitability of individual prefectures for fruit cultivation. CSI was defined as a growing period mean of the deviation of monthly RQ from RQmax which is the RQ at the maximum yield of fruit. Linear relationship was found between long-time average of fruit yield and CSI for major fruit producing prefectures, showing that CSI can be used to evaluate the agroclimatic suitability of each prefecture for fruit cultivation. Weather data were treated to make clear the spatial distribution of CSI over Japan. Major producing areas of peach and Japanese pear were found to locate in the area with CSI above 70-80. CSI distribution map is also applied to evaluate regions suitable for the cultivation of grape (European, North-China, and American species) apple, cherry, persimmon, chestnut, and so on.
  • 楊 桂清, 堀口 郁夫, 谷 宏, 元木 敏博, 大沢 和祐, 伊藤 恒雄
    1990 年 46 巻 3 号 p. 137-142
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
    This study was performed to estimate temperature using GMS IR data around Ningxia, China, as a large area (66, 000km2) with only 17 meteorological observation sites.
    The results are summarized as follows:
    1) High correlation coefficients between 1.5-m height temperature and surface temperature were obtained. These correlation coefficients have significance of 5% level.
    2) The estimated 1.5-m height temperature for from midnight to morning was good accurate, but that from daytime to early evening had large error in the large areas that include different land covers, like Ningxia.
    3) Temperatures at 02:00 am, and 08:00 am. decreased from the northern part to the southern part of Ningxia. The isotherm was almost parallel to the contour line.
    4) The night temperature (02:00 am.) in irrigated areas and a reservoir was warmer than that of the surrounding area, morning temperature (08:00 am.) was colder than that of the surrounding area.
  • 鱧谷 憲, 文字 信貴, 小元 敬男
    1990 年 46 巻 3 号 p. 143-146
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
    A short (3cm) span sonic anemometer for vertical wind component was developed using inexpensive ultrasonic transducers. Wind tunnel test indicates this anemometer can be used within the tilt angle about ±30°. A field test with a commercial sonic anemometer (span=20cm) at two heights indicates that high frequency attenuation is less for the new short span anemometer near the surface.
  • 青野 靖之, 小元 敬男
    1990 年 46 巻 3 号 p. 147-151
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
    A simplified method to estimate blooming dates of Prunus yedoensis using “the number of days transformed to standard temperature (DTS)” is proposed. The method discussed in our previous papers required rather complicated procedures. For example, to obtain optimum starting dates and the mean DTS accumulations at each site, it was necessary to have relatively long records of daily mean temperature and actual blooming dates. By the simplified method, we only need daily mean temperature for the year under consideration. For DTS, the same value DTSm (21.5 days) are used for all stations in Japan. The value is determined by using data at 38 meteorological observatories. This simplified method was tested at 20 meteorological observatories which were not used to determine starting date (D*). The test showed increase in RMSE compared with the previous methods as expected. This seemed to be attributed to introduction of a constant DTSm to all stations instead of determining the value at each station. The method is applied to estimate blooming dates at parks in western Japan noted for the cherry blossoms. It is shown that accuracy of 2-3 days of RMSE are obtained to the parks where daily mean temperature data are available within 4-5km.
  • 東アジアの世界気候影響研究計画に関するレビュー
    吉野 正敏
    1990 年 46 巻 3 号 p. 153-165
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 耕地気象改善研究部会
    1990 年 46 巻 3 号 p. 167-170
    発行日: 1990/12/10
    公開日: 2010/02/25
    ジャーナル フリー
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